The research program will be focused in seven program areas: effects of low-level, long-term exposure to environmental agents, multiple-factor interactions, environmental cancer, asbestos-associated disease, biological properties of inorganic microparticles, halogenated aromatic hydrocarbon and related chemicals and evaluation of disease potential of new suspect environmental agents. In this we are primarily concerned with human health effects and utilize population studies as an essential methodological approach, with interdigitation of epidemiological, clinical, biological and physical sciences. Because of the recognized need to evaluate the magnitude of the problems studied, environmental evaluation is regularly added to provide quantitative information concerning dose-disease response relationships, to facilitate evaluation of proposals for regulations and control, and prevention of disease. Cooperative studies with occupational groups and identified populations in the general community subject to specific exposures, provide an effective approach to such research aims and serve further to build the application of information into the process of seeking the data. Too, such investigations serve to identify groups of people which have been exposed to these agents, i.e., high risk groups. Preventive surveillance becomes feasible, in addition to modification of adverse exposure.